FISHERY BULLETIN: VOL. 71, NO. 2 



at that time. Juveniles were also present in 

 July 1970 and September 1971. 



Diuphus iinderseiii 



At night, adults of D. cniderseiii occurred 

 mostly around 200 m whereas the juveniles 

 (<13 mm) were found only around 100 m. D. 

 aiiderseiii had one of the shallowest day depths 

 (Table 1) and most limited migrations of all 

 the species considered, the adults covering only 

 about 100-200 m each night. In all series but 

 March 1971, catches were mostly small juveniles 

 and adults, but in March 1971 both CT and IK 

 tows indicated the population was composed 

 entirely of intermediate-sized fish. Apparently 

 this species spawns over the greater part of the 

 year. 



D/apb//s hriichycephalits 



Numbers of D. brachycephalus were quite 

 low except in September 1970 when large 

 numbers of juveniles (<20 mm and most <15 

 mm) were collected around 50 m at night. The 

 larger individuals caught at 150-200 m were 

 mostly females. Five of the 10 larger males 

 (over 40 mm) taken at night were caught below 

 300 m, suggesting that the larger males migrate 

 little or not at all. Presence of 9- to 12-mm fish 

 in June, July, and September and their absence 

 in December and March indicated that D. 

 brachycephalia^ spawns in the summer. The June 

 and September samples included both very small 

 and adult fish; the March samples were mostly 

 intermediate sizes (15-30 mm) suggesting that 

 this species reaches adult size within 1 year. 



Diiiphiis itdenonms and 

 D. chrysorhynchns 



D. adenomus and D. chrysorJiynchiis are both 

 apparently epibenthic and associated with 

 shallow water. D. chrysorhy nchus (54-98 mm) 

 is frequently taken in bottom trawls at 75-190 m 

 at night and D. adeiiomns (41-153 mm) at 

 180-185 m at night. Both are taken down to 

 500-600 m during the day (P. J. Struhsaker, 

 pers. comm.). Individuals of the sizes taken 

 near the bottom were rarely caught in mid- 



water. The D. adenomua were all taken during 

 the day by IK. Thirteen of the D. chrysorhyn- 

 chus collected were larger fish (56-84 mm). 

 These were taken sporadically at all seasons, 

 eight of them in the upper layers at night. The 

 remaining 21 specimens were all 11-17 mm 

 and all taken in the upper layers at night during 

 the September 1971 series, 11 of them in one 

 tow at 80 m. This suggests that this species 

 spawns in late summer and that the young are 

 pelagic. Unless substantial numbers of adults 

 of these species are able to avoid both CT and 

 IK, it appears that the larger fish caught 

 pelagically were wanderers. 



Notolychmis vcddiviae 



Significant differences in size-frequency curves 

 from several series indicated that smaller N. 

 valdiviae occurred higher in the water column. 

 In both September 1970 and 1971 series, the 

 catch at night at 80-100 m was almost totally 

 <15 mm and at 115-145 m mostly over 20 mm. 

 In other series, single pairs differed significantly, 

 but trends were not as obvious because most of 

 the fish were of one size class. Two day tows in 

 September 1970 at 525 and 725 m also differed 

 significantly with 60% of the fish <20 mm in 

 the shallow tow and over 90% >20 mm in the 

 deep tow. 



In September and December 1970, night 

 catches of N. valdiviae near the day depth were 

 larger than that expected from contamination. 

 Substantial catches were also made in the 

 upper layers during these series. In September 

 1970, roughly 70% of the population remained 

 at depth. There were relatively more larger 

 fish in the nonmigrating fraction (Figure 5). 

 In December 1970, roughly 50% did not migrate, 

 but there was little difference in size composi- 

 tion between shallow and deep catches. There 

 were no significant differences in either sex 

 ratio of mature fish or ripeness of mature 

 females between the shallow and deep night 

 catches. There was no indication that any 

 sizeable fraction of the population did not 

 migrate in either March or June 1971. 



The calculated totals for day and night 

 agreed fairly closely and indicated no differen- 

 tial avoidance. Likewise, the calculated size- 



414 



